Oscillators find many applications in integrated circuits, for example to control the timing of various components and circuits. One type of oscillator is an RC (resistance-capacitance) oscillator that provides an oscillation signal by charging and discharging a capacitance through a resistance. The period of the oscillation signal generated by an RC oscillator can depend on, among other things, the magnitude of a supply voltage provided to the oscillator. Generally, the period can be defined by
                              TOSC          =                                                    (                                  C                  *                  V                                )                            IPU                        +                                          (                                  C                  *                  V                                )                            IPD                                      ,                            (                  Equation          ⁢                                          ⁢          1                )            where C is the magnitude of the capacitance being charged and discharged, V is the voltage swing of the capacitance (typically from a reference voltage, such as ground, to the supply voltage, such as VCC), IPU is the charging current (e.g., the pull-up current), and IPD is the discharging current (e.g., the pull-down current). In order to help provide a stable oscillation signal period, the supply voltage is regulated in some integrated circuits. However, a voltage regulator can occupy space on and consume power in an integrated circuit, both of which may be undesirable in some instances, such as in integrated circuits designed for portable devices.
If the supply voltage for an RC oscillator is left unregulated, though, the capacitance may be charged to (and discharged from) higher or lower voltages at slower or faster charge (and discharge) rates. Furthermore, the characteristics of the capacitance may vary depending on the voltages provided to the different nodes of the capacitance (e.g., the capacitor may not have a substantially constant capacitance-voltage (C-V) characteristic curve). These variations may, in turn, cause the period of the oscillation signal provided by the oscillator to vary responsive to changes in the supply voltage provided to the oscillator.